// 3 Stacks
// Get sum of even fibonacci numbers below 4000000
PUSH 0 1
PUSH 0 1
PUSH 1 0 // Total

JMP start

:sumIfAble
PUSH 0 s0
PUSH 0 2
MOD 0
JZ 0 sum
POP 0
RET
:sum
POP 0
PUSH 1 s0
ADD 1
RET

:start
CALL sumIfAble
PUSH 1 s0
POP 0
PUSH 2 s0
POP 0
PUSH 0 s1
PUSH 0 s1
PUSH 0 s2
ADD 0
POP 1
POP 2
PUSH 1 s0
PUSH 0 4000000
PUSH 0 s1
POP 1
SUB 0
JN 0 end
POP 0
JMP start

:end
POP 0
WRITE s1